1. Field of the Invention
The present invention relates to a backlight module, a light source module used therein, and a manufacturing method thereof. Particularly, the present invention relates to a backlight module utilizing the light-mixing technique, a light source module used therein, and a manufacturing method thereof.
2. Description of the Related Art
Display panels and flat panel displays (FPDs) utilizing display panels have gradually become the mainstream display devices nowadays. For example, panel screens, household flat-panel TVs, flat-panel screens for personal computers or laptop computers, display screens for mobile phones or digital cameras, etc. are products in need of display panels. Especially for the increasing market demand for liquid crystal displays (LCD), the design of backlight module for LCDs is getting diverse to meet the functional and exterior appearance requirements of LCDs.
Taking the edge type backlight module as an example, light emitting diodes (LEDs) have been employed as the light source. As shown in FIG. 1A, the backlight module includes an optical plate 10 and a light bar 30. A plurality of LEDs are disposed in a straight line to serve as the light source. In general, backlight modules adopt white LEDs as the source. However, due to limited process control of phosphor coating, the unevenness in chroma or color easily happens in white LED products. As shown in FIG. 1B, the spectrum distribution in a color space of white LEDs manufactured in the same manufacturing process usually forms a band, which has one end near the yellow light range while the other end near the blue light range. In order to provide a desired chromatic uniformity and to meet the standard white color screen, the common practice is to adopt the white LEDs of same chromaticity such as the LEDs having color coordinates falling into a specific zone 50. As described above, the white LEDs in a same manufacture batch, which have color coordinates falling outside the zone 50, can not be utilized, and therefore the cost is increased.
In some designs, special optical plates or packages are adopted to resolve the color unevenness problem of LEDs. However, this solution generally decreases the luminous efficiency and the brightness and increases the cost.